1. Technical Field
The present invention relates generally to an intake manifold for a vehicle with a unified gas flow path and, more particularly, to an intake manifold for a vehicle with a unified gas flow path in which the flow path of a PCV valve connector for receiving blow-by gas and the flow path of a PCSV connector for receiving fuel evaporation gas are integrated.
2. Description of the Related Art
In general, an automotive engine has one or more cylinders each being constituted by a cylinder head and a cylinder block, and kinetic energy produced by combustion of a gas mixture of fuel and air with an appropriate ratio in the cylinders is used for driving a vehicle.
The cylinders of the automotive engine are connected to an intake manifold, so the intake manifold is a part of the automotive engine for supplying the mixture of fuel/air into the cylinders.
The intake manifold is a part for uniformly distributing a combustion mixture (or air in a direct injection engine) to intake ports of the cylinder heads.
Meanwhile, combustion gas and non-combustion gas produced by explosion in the cylinders of an engine flows into a crankcase through the gaps between pistons and the cylinder liners and this gas is called blow-by gas. The inside of the engine is corroded or engine oil is easily changed in quality by the blow-by gas. Accordingly, a blow-by gas recirculation system that circulates blow-by gas into the cylinders of an engine by sending it back to the intake side is installed.
Blow-by gas in a crankcase is sent into the intake manifold of a vehicle through a PCV (Positive Crankcase Ventilation) by such a blow-by gas recirculation system. The blow-by gas sent in the intake manifold is mixed with fresh air in the intake manifold and then flows back into the cylinders of the engine.
Further, fuel evaporation gas produced in a fuel tank is collected and kept in a canister, sent into a serge tank of the intake manifold through a purge control solenoid valve (hereafter, referred to as a PCSV), and then supplied into the cylinders.
The PCSV is a valve for diffusing fuel evaporation gas produced in a fuel tank and collected in a canister to the engine.
FIGS. 1 to 3 show an automotive intake manifold of the related art. Referring to FIGS. 1 to 3, an automotive intake manifold 1′ has a plurality of branch pipes 10′ connected to the intake ports of the cylinders of an automotive engine, and a surge tank unit 20′ that is connected to the branch pipes 10′ and has an external air inlet formed at a side to receive external air.
A blow-by gas inlet 20a and an evaporation gas inlet 20b are formed with a predetermined interval in the surge tank unit 20′ of the automotive intake manifold 1′ so that blow-by gas and fuel evaporation gas flows into the surge tank unit 20′.
The blow-by gas inlet 20a is connected to a PCV valve connector 30′ protruding to connect a PCV valve and the evaporation gas inlet is connected to a PCSV connector 40′ protruding to connect a PCSV.
Further, the blow-by gas inlet 20a and the evaporation gas inlet 20b are spaced from each other at an external air inlet 23′ of the surge tank unit 20′ so that external air, blow-by gas, and evaporation gas can be mixed well in the surge tank unit 20′.
However, since the blow-by gas inlet 20a and the evaporation gas inlet 20b are spaced from each other at the external inlet 23′ in the automotive intake manifold 1′ of the related art, when external air flows into the surge tank 20 through the external air inlet, a loss of pressure of the air is caused by flow resistance, so the external air cannot smoothly flow into the surge tank unit 20, and accordingly, air cannot be sufficiently supplied into cylinders.
Further, according to the automotive intake manifold 1′ of the related art, since high-temperature blow-by gas is supplied into the surge tank unit through the blow-by gas inlet 20a, condensate water is produced in the blow-by gas inlet 20a when the high-temperature blow-by gas is mixed with cold external air in winter and, the condensate water partially or fully blocks the blow-by gas inlet 20a by freezing.